The fabrication of the next generation of advanced, multifunctional semiconductor devices that interlace optoelectronic, telecommunication, and conventional complementary metal oxide semiconductor (CMOS) components requires growth of lattice-mismatched systems. Lattice mismatched systems can provide a wide range of materials characteristics. For example, the mechanical stress in a lattice mismatched layer and control of its crystal symmetry can be used to modify the energy-band structure to optimize performance of optoelectronic devices. Lattice mismatched systems can also enable compound semiconductor devices to be integrated directly with silicon (Si) circuitry (e.g., Si-based CMOS circuitry).
For the integration of compound semiconductor epilayers on Si, problems arise due to the lattice mismatch between the epilayer and the underlying Si, and this mismatch is often exacerbated by their thermal expansion coefficient mismatch. The performance of integrated devices has been largely limited by the resulting crystalline defects from epitaxy (e.g., a high density of dislocations).
Thus, there is a need to overcome these and other problems of the prior art and to provide techniques for growing high-quality epitaxial layers of lattice mismatched systems.